Method and device for generating phase-coherent light pulses

• US 6,038,055 A
• Filed: 11/12/1998
• Issued: 03/14/2000
• Est. Priority Date: 11/13/1997
• Status: Expired due to Term

• Current Assignee: Max-Planck-Gesellschaft Zur Foerderung Der Wissenschaften e.V. (Max-Planck-Gesellschaft zur Frderung der Wissenschaften e)
• Original Assignee: Max-Planck-Gesellschaft Zur Foerderung Der Wissenschaften e.V. (Max-Planck-Gesellschaft zur Frderung der Wissenschaften e)
• Inventors: Heupel, Tilman, Weitz, Martin, Hansch, Theodor
• Primary Examiner(s): Ben, Loha
• Application Number:
  US09/190,832
• Time in Patent Office: 488 Days
• Field of Search: 359/264, 359/279, 359/305, 372/18, 372/25, 372/28, 372/30, 372/32
• US Class Current: 359/279
• CPC Class Codes: H01S 3/0085 Modulating the output, i.e. the laser beam is modulated outside the laser cavity
• CPC Class Codes: H01S 3/082 defining a plurality of resonators, e.g. for mode selection or suppression
• CPC Class Codes: H01S 3/117 using intracavity acousto-optic devices

Abstract

For the generation of amplified, phase-coherent light pulses, a sequence of phase-coherent, equidistant input light pulses (21) is coupled into a resonator device (1) with at least two resonator mirrors (11, 14), forming a light path (10) with a predetermined resonator length, in such a way that the coupled in input light pulses in the resonator device are linearly superimposed in succession to form at least one circulating light pulse, whereby the circulating light pulse is coupled out of the resonator device as an output light pulse (31) as soon as the circulating light pulse has reached a preset minimum level of energy.

Claims

1. Method for generating phase-coherent light pulses in which a sequence of phase-coherent, equidistant input light pulses is coupled into a resonator device with at least two resonator mirrors, forming a light path with a predetermined resonator length, in such a way that the coupled-in input light pulses in the resonator device are linearly superimposed in succession to form at least one circulating light pulse, whereby the circulating light pulse is coupled out of the resonator device as an output light pulse after the circulating light pulse has reached a preset minimum level of energy.

2. Method according to claim 1 in which the output light pulse is coupled out by a modulator element with which the output light pulse can be deflected from the light resonator.

3. Method according to claim 2 in which the modulator element is actuated for output coupling after a detector device has determined that the circulating light pulse has reached the preset minimum level of energy.

4. Method according to claim 2 in which the modulator element is actuated for output coupling after a preset number of input pulses has been coupled into the resonator device.

5. Method according to claim 1 in which n circulating light pulses (n=natural number) are generated in the resonator device, whereby one circulating light pulse is superimposed with input light pulses that are spaced n light pulses apart.

6. Method according to claim 1 in which the input light pulses and the circulating light pulse are matched in phase in that the wavelength of the input light pulses or the resonator length of the resonator device is set by a control signal dependent on the effectiveness of coupling input light pulses into the resonator device.

7. Method according to claim 6 in which the input light pulses are RF modulated and the control signal is derived from the signal of a detector detected in turn by a phase-sensitive detector and corresponding to the fraction of input light pulses reflected from an input coupling mirror of the resonator device.

8. Resonator device for light pulse amplification consisting of:

at least two resonator mirrors forming a light path with a preset optical resonator length, whereby the first resonator mirror forms an input coupling mirror for phase-coherent input light pulses and the light path is free of amplification media, and

a modulator element for coupling at least one output light pulse out of the light path, whereby each output light pulse represents a linear superposition of a plurality of input light pulses.

9. Resonator device according to claim 8 in which the input light pulses form a pulse train with constant pulse spacing in time, whereby the optical resonator length corresponds to the product of pulse spacing and velocity of light of integral multiples or parts of it.

10. Resonator device according to claim 8 in which the modulator element is an acousto-optical modulator.

11. Resonator device according to claim 8 in which a detector device is provided to detect the energy of a circulating light pulse.

12. Resonator device according to claim 11 in which a controlling device is provided that issues a switching signal to the modulator element after the detector device has determined a preset minimum level of energy of the circulating light pulse, a predetermined number of input pulses has been coupled into the resonator or an external signal has been received.

13. Resonator device according to claim 8 in which at least one resonator mirror is provided with an adjusting device for altering the resonator length.

14. Resonator device according to claim 8 in which a device for dispersion compensation is provided.

15. Resonator device according to claim 8 in which a device for wavelength stabilization is provided that comprises a modulator device for modulation of the input light pulses, a detector device for detection of the fraction of input light pulses not coupled into the resonator device, a modulator source and a phase detector for phase-sensitive detection of the signal of the detector device and for generation of a control signal for wavelength stabilization.